Screening and refining of fiber



Aug'. 14, 1934.

Patented Aug. 14, 1934 PATENT OFFICE t l 1,910.33 SCREENING Ann v:terminer or man William H. Mason, Laurel, Miss., assignor to Masonite Corporation, Laurel, Miss., a corporation of Delaware Application Jllne 17, 1932, Serial No. 617,786

zo claims.

My invention relates to screening and renning; and particularly to a process and apparatus that eliminates need for separate screening, and combines the functions of screening and refining.

A principal object of the invention is the provision of means for performing a screening operation which is entirely free from clogging and permits the free passage of pieces or particles which are already below a predetermined size, without lexpenditure of unnecessary rening work thereon, and which is also adapted for reducing any coarser pieces or particles below such limiting size, whereupon the same are freely and l5 quickly passed through along with the originally smaller pieces or particles, with the minimum of work uselessly (or harmfully) expended in producing unnecessary refinement.

The invention is of general application, but apparatus for carrying out my new process is especially well adapted Afor screening and for refining of vegetable fiber for manufacture of fiber boards, as for example, porous insulation board made by drying a wet lap of the ber, or hard dense board made by hot-pressing and having a specic gravity of about .9 to about 1.1, may be advantageously made from such fiber.

Fiber when used in making ber boards need not be highly rened, but does require a sumcient state oi' refinement or subdivision oi the coarser parts to permit the fiber to be readily formed from water into a smooth blanket or sheet or so-called wet-lap, as in a Fourdrinier or equivalent wet machine.

When her is made from hard or soft Woods, as for example by progressive discharge through constrlcted outlets from under high pressures, as taught in my Patent No. 1,578,609, granted on March 3o, 1926, the resulting so-called ruw ber contains quite a large proportion, as for example say 56% oi' fines which are already suiciently reduced in size so as to be ready for use and reduire no further refining treatment, either in the way oi reduction in size or in length, and there is also a proportion ci coarser material in the nature of iiber bundles, which requires rehnement for securing reduction to the predetermined size found necessary to get a smooth, even wet-lap, while at the same time it is desirable to maintain the ber length to the greatest possible extent.

With the present invention it becomes possible to avoid the necessity of preliminary screening for separation of the ner from the coarser pieces or particles, and to put the entire ber material, such as gun fiber for example, with only perhaps removal of some chip-like pieces, through a single treatment which performs the screening function at the same time that it does 60 the refinement work required to reduce the larger pieces to the desired size. Of course, if the material treated is all relatively coarse, then the screening action is conned to removal of the fines as rapidly as produced through the refining action performed on the coarse fiber.

With my invention the entire work done on the pulp or other material to' be treated is accom- A plished in a very short pathI of travel of the mate rial, usually a travel only an inch or two in length Abetween relatively rotating surfaces which are preferably roughened, and a number of such possible paths of travel are preferably provided, arranged in' parallel, whereby increased rapidity of ow can be obtained and largequantities of material treated.

I preferably obtain such paths of travel in parallel by providing same between rotating ringshaped members, and arrange such members in sets which are rotatable relative to one another, as for example, one set may be Astationary and the other rotatable with respect thereto, or one set may rotate in one direction While the other rotates in the opposite direction, or both may rotate in the same direction, but at different speeds.

I have illustrated a preferred form of apparatus in the accompanying drawing, in which- Figure 1 is a longitudinal sectional view, and

Fig. 2 is a fragmentary detail sectional View on the line 2 2 of Fig. 1.

The illustrated apparatus is contained in a hollow circular casing 10, made in two, preferably substantially like, portions 12 and 14 secured together along the medial line by bolts 15 for ease in msembly and take-down.

One of the casing members l2 is provided with an axial'opening 16 for admission of .the pulp to be treated, and the other member 14 provided with a similar preferably axial outlet 18 for the exit passage of the screened and/or refined pulp. 100

Conduit necks such as 20 and 22 with flanges 2i and 26 may be supplied for the convenient. attachment of supply and outlet conduits, and are preferably directed .at right angles to the axial line of the casing so as to be out of the way of 105 the shaft and operating mechanism. 'I'he pulp may be pumped or supplied under a gravity head if desired.

In the simplest form, the casing is provided l withv a stationary spider 28 comprising radial lo' arms 30 with openings 32 therebetween, the spider arms 30 being connected by .inner and outer ring portions 34 and 35, the former resting against and backed up by the casing collar 36 containing the holes 3'7 through which the material passes on its way to the axial outer passage' 18. I provide a series of concentric renner rings 38 and attach same to the spider 28 as by bolting same within annular grooves or notches 40 provided to receive and hold same. Such rings 38 are widest at their Abases 42 where they are bolted to the spider 28,

and they have preferably like tapering sides 44, 44 terminating in a narrow edge portion 46 on the face thereof furthest from the spider 28. The outermost ring 38' is preferablytapered only on its inner face and has a fiat outer face which is received within groove parts 39, 39' in the casing members 12 and 14 respectively, and securely clamped in place and held against rotation by the bolts 15 that secure the two halves of the casing together. The width of the taper faces 44 is but a small fraction of the ring diameter.

The shaft 50 extends axially through the casing 10 with provision against leakage as by means of glands 52, 54, and the drive means therefor, consisting preferably of an electric motor with a reduction gear (not shown), has driving connection to the shaft 50 by means of a slide coupling 55 which will permit longitudinal movement of the shaft 50 without interfering with the drive.

Provision is made preferably beyond the opposite or exit side, of the casing 10, for adjusting the shaft'50 longitudinally, for a purpose to be referred to later,.and in the form shown, shaft 50 runs in a ball bearing 60, and the inner annular bearing member 62 thereof is attached to suchy shaft 50 so as to be restrained from longitudinal movement with respect thereto. As shown this connection consists in interposing the inner bearing member or ring 62 of the ball bearing 60 between the lshoulder 64 of the shaft 50 and the flanged plate 66 bolted to the end of shaft 50.

The means for moving the bearing 60 and thereby adjusting the shaft 50 endwise is attached to the casing 68 which receives the outer member 70 of the ball bearing, and preferably consists of a screw threaded shaft 'l2 secured to the casing member of the ball bearing at '14. and having the hand wheel member 'l5 screwed thereon and having its hub provided with a groove 76 to receive a preferably split collar 'I8 of the bearing housing 80, said hand wheel 'I5 thus serving when turned for moving -the ball bearing 60 forward or back and thereby yadjusting shaft 50 longitudinally, and the screw threaded locking wheel member 81 can be tightened up for locking the parts in various adjusted positions.

The shaft 50 is formed with a shoulder 51 and has keyed thereto withinthe casing 10, a spider 82 having radial arms 84, a hub 86 engaging shoulder 5l, and an outer connecting ring88 with openings 89 between the radial arms. (The openings 32 in the stationary/spider 28 are similar to the openings 88 of rotatable spider 82 as shown in Fig. 2.) rings are boltedk to spider 82, being received in positioning grooves or notches 92. These rings 90 are of a size to face the openings between the renner rings 38 of the stationary spider 28, and said rings 90 have short tapering outer face portions' 94 adapted to enter between the tapered parts 44 of the stationary rings 38, but are rather narrow and fiat sided at their rearward por- M-ons so as to leave the tapering entrance passages 96 between parts 44, and so maire a relatively wide mouth The concentrically arranged renner them and such tapered face at 96 with convergingv walls for easy entry of any coarse pieces of material between the coacting tapering parts.

By adjusting the shaft 50 endwise by means of the hand wheel 75 provided for such purpose, the spider 82 may be adjusted with respect to spider 28, and the annular passages at A between the tapered rings 38 and 90 may be made as wide or narrow as desired, and the parts locked in such position by means of locking wheel 81. The length of the passages A, which determines the distance the material travels in passing through the passage, is relatively short and depends principally on the width of the taper faces of the reflner rings as 44, 94. Both the length and width of the passages A. are preferably a small fraction of the annular passage diameter.

The pulp or other material to be treated and supplied as by pumping or under gravity head to the inlet side, in order toreach the outlet side must pass through the annular passages A between the refiner rings adjusted to whatever predetermined spacing may be desired.

The `ber is handled in low concentration in a pulp with water, the content of dry fiber by weight being desirably under 4% by weight of the total pulp and preferably around 1/2% or 1% thereof.

'I'he pieces or particles of fibers or bundles of fibers which are sufficiently small pass with the water stream freely through the annular passages A. In the case of fibrous materials too coarse to pass through immediately, there is a rolling action thereon obtained between the co-acting faces of the reflner rings which is 'tion of a long fiber product andas soon as the breaking-down and refining action has proceeded with the small bundles of fiber to such extent that they are sumciently fine to pass through the openings A, they pass therethrough and go on with the current, leaving other coarser parts to be similarly reduced and sent Ion 'to the exitside of the mechanism.

With my invention numerous features of advantage are obtained. The rings can be made of metal, stone composition and the like, and can be readily removed for roughening to provide attrition to any desired extent. Substantially anydesired capacity can be obtained by choice of the number of refining and screening rings. Substantially any desired treatment may be given as for example, the new machines may be arranged in a series of two or more with successively closer settings. No clogging can take place as happens with certain types of screens as the walls of the passages are in relative movement so that the stock is kept moving and passes through with the current.

Unnecessary and possibly harmful overreflning is eliminated, no separate screens are needed, and other' items of advantage include saving in power requirements, production of long fiber refined pulp, high capacity, simplicity, cheapness and accessibility of parts'.

I claim: l

1. In a combined screening and refining apparatus for unevenly comminuted material, a pair of relatively rotating members each provided with a plurality of concentric rings having taper faces, the rings on the respective members being arranged to provide a plurality of passages therebetween for material treated.

2. Apparatus as in claim i, in which the width of the taper ring faces is a small fraction of a ring diameter.

3. Apparatus as in claim ll, in which the memlfavorableto the producbers of thepair are movable toward and away from one another, and in which means are provided for producing such relative movement and thereby adjusting all the rings of a set simultaneously with respect to those of the other set.

4. In a combined screen and refiner for pulp of vegetable fiber or the like, a casing provided with inlet and outlet, two sets of relatively rotating substantially concentric ring members with co-acting taper faces within the casing and between which material traversing the casing from inlet to outlet must pass, and means applied to all the rings in aset for producing relative adjustment of said ring sets toward and away from one another.

5. Apparatus as in claim 4, in which the width of the taper ring faces is but a small fraction of the ring diameter.

6. Apparatus as in claim 4, in which one of the sets of concentric rings is fixed in the casing, and the other is rotatable therein.

7. Apparatus as in claim 4, in which one of the sets of tapered rings is fixed in the casing and the other is rotatable therein, with means for adjusting the rotatable set of rings toward and away from the fixed set of rings, said adjusting means applying alike to all the rings of the rotatable set.

8. Apparatus for screening and refining of vegetable fiber and thelike pulp, comprising a casing with inlet and outlet, a shaft extending axially through said casing, a spider fixed in the casing, concentric taper-faced rings on said spider, a second spider fixed on the shaft to turn therewith and facing the first named spider, a series of concentric taper-faced rings on said last named spider, and adapted on longitudinal movement of the shaft to be received between the taper-faced rings on the first named spider, and

means for the longitudinal adjustment of said shaft.

9. Apparatus as in claim 8, in which the width paratus, a casing provided with inlet and outlet, two sets of relatively rotating ring members in said casing with co-acting -ftaper faces, providing a number of passages therebetween for material treated having a width which is a small fraction of a part ofthe ring diameter, said pasp'ulp is passed through an sages having an enlarged mouth part converging to a relatively narrower portion ywith substantially parallel walls.

12. The process of treating vegetable fiber to produce limited refinement of coarse fiber bundles While substantially maintaining the fiber length and to pass along the finer portions freely without material refinement thereof, which comprises passing same in low concentration in water through a substantially annular passage of substantially like width all the way around, rand of length which is a small fraction of the diameter, while subjecting the coarser portions to attrition by producing relatively rotary movement of the substantially continuous walls defining the -annular passage.

13. Process as in claim 12 in which dry fiber is under 2% of the pulp by weight.

14. Process as in claim 12 in which the watery at its mouth. y

15. Process as in claim 12 in which by weight dry fiber is under 4% of the pulp and the watery pulp is passed through an annular passage widest at its mouth. t

16. Process as in claim 12 in which the watery pulp is passed. through a plurality of annular passages concentrically disposed and which afford a plurality of paths in parallel for the travel of the pulpannular passage widest 106 17. Process as in claim 12 in which the watery pulp is passed through a plurality of annular paths Widest at their mouths and which are concentrically disposed and afford a plurality of paths in parallel for the-travel ofthe pulp.

18. Process as in claim 12 in which by weight dry fiber isunder 2% of the pulp and the watery pulp is passed through a plurality of annular passages widest at their mouths and which are concentrically disposed and afford a plurality of paths in parallel in the travel of the pulp.

19. A combined screening and refining apparatus for comminuted material in low concentration in water comprising a pair of relatively rotating concentric members providing between them an annular passage of substantially uniform width all the way around, which width is a small fraction of the annulus diameter, and

the length of which passage is likewise a small fraction of the annulus diameter, and supply andl exit means for watery pulp of the comminuted material on the respective sides of the short, narrow, annular passage.

20. The apparatus of claim 19, and in which the member defining one wall of the passage is flxed, and the member defining the other wall is rotatable.

` WILLIAM H. MASON. 

